<!DOCTYPE html>
<html lang="en">

<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>相对路径</title>
</head>

<body>
  <!-- 1.jpg -->
  <img src="./1.jpg">

  <!-- 2.jpg -->
  <img src="./images/2.jpeg">

  <!-- 3.jpg -->
  <img src="../3.jpg">
</body>

</html>